The Short Brothers were well known to me by name for a good many years before I had the pleasure of meeting any of them personally. That was when I joined the Company in the middle of 1916. It must I think, therefore, seem strange to you that the honour, a very real one to me, of being invited to give this first lecture to commemorate their great pioneering work, should fall to me.

A big part of the span of man's life has passed since they began their activities; many of their contemporaries and friends of those early days have either passed on or have reached a ripe old age. It may well be that I know the brothers personally better than any one else living. Be that as it may, I am quite sure that none holds them in greater esteem.

The aims of structure weight estimation are discussed and a review is given of its development in this country during the past fifty years from the simplest of formulae to quite detailed methods. The limitations of formulae derived only from statistical analysis of actual aircraft structures are noted. For aircraft of novel configuration it is essential for the weight of the basic load-carrying structure to be estimated by methods which are based upon the actual design and stressing procedures. The principles of “optimum” or “minimum-weight” structural design are a valuable feature of such methods and are briefly described. Statistical analysis, however, is still important for estimating the substantial weight of the joints, cutouts, transparencies and other features which transform a theoretical optimum structure into a complete and practical one. The problems of several aeroplane and missile configurations of current interest are discussed, and also the extent to which detailed design work is necessary to provide reliable structure weight estimates for such projects.

The problem of the vibrations induced in an aircraft structure excited by jet noise has been solved mathematically in general terms by Powell and others. The most promising methods for dealing with a practical structure are those based on the normal mode approach. In these methods the response of the structure in each of its normal modes is first determined and then the total response is obtained by a summation of individual responses. Use of these methods on practical structures is tedious because of the large number of modes which must be considered and also the difficulty of calculating theoretically the normal modes of a practical stiffened structure.

R. K. Pierson was a great man, not least physically. I can still see those huge shoulders, the hands thrust into the coat pockets, the magnificent head, and the aggressive chin. It is not for me to deliver a eulogy of R. K. P. and his work at Vickers—that has already been well done. But I must say how honoured I feel at being asked to give, on this occasion, the lecture which you arrange annually in memory of an outstanding designer.

My recollection of him goes back to 1933. In the long vacation of that year, as an undergraduate, I crept into the flight sheds at Weybridge for an eight weeks indoctrination from Industry. Rigging Virginias, Victorias and Vildebeestes was the main occupation, with some analysis of flight tests if you showed willing, and banishment to the main shops across the airfield— knocking rivets into Vildebeeste wireless containers— if you were naughty. I enjoyed it so much that I came back for a similar period in 1934 just after graduating. The family atmosphere and team spirit were very marked —Pierson used to rush into the flight office with his pipe and tear through the test flight reports with Mut. Summers; he was quite willing to deal kindly with some diffident and probably idiotic remark put forward by a vacation apprentice clutching a bundle of grubby graphs prepared for Radcliffe—who in those days was the mainstay of the flight test Department (he was outnumbered by the test pilots—there were two of those).

Brearey was a most energetic Honorary Secretary. His belief in the ultimate success of the cause which he had taken up in the fiftieth year of his life with such enthusiasm was practically demonstrated by the many aircraft models with which he experimented and the lectures he gave. As has already been noted, he was not content with encouraging an interest in Aerial Navigation by means of the Aeronautical Society, but he founded the Aeronautical Club, where the more enthusiastic members could meet on the third Tuesday in each month and discuss their ideas in private. It was owing to the meetings of this Club that public lectures were arranged and demonstration given at the Annual Meetings of the Society.

In 1931 Peters showed that flow entry conditions had a marked effect on diffuser performance. Later, Winternitz and Ramsay indicated that the pressure recovery coefficient Cp of a conical diffuser might be regarded as a linear function of β(θ/d)i for values of β(θ/d)i up to 0·1. This note draws attention to the fact that diffusers with much larger values of this parameter are of interest and presents some experimental and theoretical results. Work is continuing along the lines indicated.

Recent lunar and planetary return vehicle studies have stimulated interest concerning the effect upon stagnation point heating due to electronic heat conduction associated with re-entry at speeds greater than 30,000 ft./sec. In order to provide experimental data for comparison with theory, a series of experiments was undertaken in which shock tube techniques were utilised for the measurement of the stagnation point heating of a blunt body over a stagnation enthalpy (Hst/RT0) range of 650 to 900, corresponding to velocities between 32,000 ft./sec. and 39,000 ft. /sec. respectively. The tests were performed in a 1·5 inch diameter shock tube with 3 foot length driver and 16 foot length driven section.

The equations showing how to correct for the effect of non-uniformity of the Atmosphere when computing the angle-of-climb (or descent) are well known and can be found in Refs. 1 and 2.

From Ref. 1, a climb at constant Mach number M implies a factor F on the Aircraft Weight to give the true angle-of-climbs (in our units for R) given by the expression

The general problem of the flow through screens has been widely studied, but certain difficulties have arisen in the comparison of screens of various solidities. A theoretical treatment and some experimental work on the flow through screens of low solidity are described below.